Forces loyal to Cote d'Ivoire's incumbent president have repulsed an attack on the bunker where he remains holed up after fierce battles with troops backing his internationally recognised rival forced him into hiding.

The attack on Wednesday raised doubts on whether Laurent Gbagbo, who lost an election and has scoffed at calls to quit, will leave power soon and came after France, which maintains ties with its former colony, declared on Wednesday that Gbagbo had only hours to go.

A spokesman for Alassane Ouattara's forces, Yves Doumbia, said they had breached the gates of the president's compound when they were repelled by heavy arms fire.

"We retreated but we are preparing for a second assault," Doumbia said.

Issiaka Konate, Ouattara's spokesman in London, told Al Jazeera that the troops had been called back and were being reorganised.

"There were a lot of fighters within the compound [of Gbagbo] ... and a lot of heavy weapons ... This is not going to be an easy job," he said.

"We realise that we had to reorganise the troops and see how this job could be done as quickly as possible."

Gbagbo's forces continued to roam the streets and broke into the Japanese ambassador's residence overnight, forcing him and seven other employees to take shelter in a safe room, Japanese media reports said.

French forces destroyed military vehicles belonging to Gbagbo's troops during a helicopter-borne mission that rescued Yoshifumi Okamura, said Thierry Burkhard, the French armed forces spokesman.

The United Nations, which has 8,000 peacekeepers in the west African country, says at least 400 people have been killed in fighting related to last November's disputed presidential runoff which led to the formation of two parallel governments - one led by Gbagbo and the other by Ouattara.

International charities have told of massacres in the country's west where at least 1,000 people have been killed in the past couple of weeks. The claims cannot be independently verified.

The UN, which organised the disputed election, recognised Ouattara as the winner with 54 per cent of the vote - Gbagbo polled 45 per cent - and has also been recognised by the African Union and ECOWAS, the economic bloc in west Africa.

A UN spokesman in New York said talks with Gbagbo's camp were continuing, but it was not clear if they would lead anywhere, especially as Gbagbo himself told French radio he had no intention of stepping down.

Gbagbo, who had put off elections several times before November's vote, has used state television to lambaste foreign forces, mainly France, which he says is backing Ouattara to protect its economic interests in the country.

UN helicopters fighting alongside French troops bombarded Gbagbo's heavy weapons stockpiles earlier this week, including those near his residence - but those attacks ended on Tuesday.